This invention relates to a method of, and device for, connecting two substrates, and has especial, but not exclusive, application to connecting together the inner conductors of two coaxial telecommunication cables, each cable comprising an outer, relatively rigid tubular conductor and an inner conductor held coaxially within the outer conductor by, for example, a plurality of disk-like spacers positioned at intervals along the length of each cable, that is to say so-called "air spaced" coaxial cables.
When connecting such cables it is imperative that neither the outer conductor nor the inner conductor is distorted. Distortion of the conductor, for example kinking of the outer conductor or rendering the inner conductor and its associated outer conductor eccentric with respect to each other, tends to produce an imperfect impedance match at the connection which can result in signals carried by the cables being distorted or garbled.
It has been proposed in British patent application No. 13584/73 filed on Mar. 21, 1973 (German Offenlegungsschrift No. 24 13 734 laid open on Oct. 17, 1974), the disclosure of which is incorporated herein by reference, to connect the inner conductors of two coaxial cables using an electrically conductive member, for example a metallic sleeve, one end of which receives the inner conductor of one cable and the other end of which receives the inner conductor of the other cable. An electrical connection is then made between the sleeve and the conductors by, for example, soldering or crimping. That application also describes the use, in conjunction with the metallic sleeve, of two cap-shaped spacers, one positioned on each end of the sleeve, or in the embodiments specifically described in that application, on a heat shrinkable sleeve surrounding the metallic sleeve. These spacers ensure inter alia that the inner conductors, and the splice between them, are correctly located with respect to the electrical connection between the outer conductors. In order to install the sleeve and cap-shaped spacers around the inner conductors of the cable it is necessary for the cables to be flexible or, if cables with rigid outer conductors are to be joined, for one of the cables to be longitudinally movable so that the sleeve can be slid over the bared inner conductor of one cable without the need to bend, at least to any substantial extent, that cable, and the other cable can then be moved longitudinally until the inner conductor of that other cable is received within the sleeve. During this operation the outer conductors of the cables are received in or over their respective cap-shaped spacers. The electrical connection between the sleeve and the inner conductors can then be made.
It is often the case, however, that neither cable is longitudinally movable and, in order to use the above-described connecting sleeve, it would be necessary to kink the inner conductor of at least one of the cables, or to strip a considerable length of outer conductor from at least one of the cables. As mentioned above, kinking could produce undesirable results.